Finally got it to actually compile

code/game/objects/items/melee/concussive_hammer.dm

@@ -6,16 +6,27 @@
 	inhand_icon_state = "default"
 	attack_verb_continuous = list("strikes")
 	attack_verb_simple = list("strike")
-	actions = list(/datum/action/cooldown/spell/concuss)
-
 	slot_flags = ITEM_SLOT_BELT + ITEM_SLOT_BACK
 	w_class = WEIGHT_CLASS_HUGE
+	var/datum/action/cooldown/spell/touch/concuss = new
 
+/datum/action/cooldown/spell/touch/concuss
+	name = "Concuss"
+	desc = "TBD"
+	background_icon_state = ACTION_BUTTON_DEFAULT_BACKGROUND
+	overlay_icon_state = "bg_default_border"
 
 /obj/item/melee/concuhammer/Initialize(mapload)
 	. = ..()
 	AddComponent(/datum/component/two_handed)
 
-/datum/action/cooldown/spell/concuss
-	name = "Concuss"
-	desc = "TBD"
+/obj/item/melee/concuhammer/equipped(mob/living/owner, slot)
+	. = ..()
+	if(slot & ITEM_SLOT_HANDS)
+		concuss.Grant(owner)
+
+/obj/item/melee/concuhammer/dropped(mob/living/owner, slot)
+	. = ..()
+	if(owner.get_item_by_slot(ITEM_SLOT_HANDS) == src)
+		concuss.Remove(owner)
+